Barrier and compressor for controlling cooling in a hermetically cooled motor

Abstract

A barrier for controlling cooling within a sealed cooled motor and a compressor including the barrier are provided. The barrier includes an insulator, at least one fastener, and a vent. The insulator restricts flow of working fluid between a first side and a second side. The at least one fastener secures the insulator. The vent controls a pressure differential between the first side and the second side. The vent can include at least one hole through the insulator. The vent can be provided as a hole through the insulator for a rotating shaft of the compressor.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 967,620, filed on January 30, 2020, the entire contents of which are hereby incorporated herein by reference. Background Technology

[0003] Hermetically cooled motors (such as the magnetic drive motors of centrifugal compressors) can use refrigerant for cooling. This refrigerant can be introduced into the compressor in either the liquid or gas phase. Because refrigerant in the liquid phase has a greater capacity to absorb heat than refrigerant in the gas phase, it is advantageous to inject refrigerant in the liquid phase into the compressor in certain situations.

[0004] Refrigerant can be used by magnetically driven compressors to provide cooling to electric motors (e.g., rotors) and magnetic bearings. The compressor bearings typically support the compressor's rotating shaft. The rotor is typically mounted to the rotating shaft. To cool these components, refrigerant is injected into the compressor (e.g., in the liquid phase). Refrigerant injection is typically accomplished using a fixed orifice, which, when the compressor is operating at maximum load, injects refrigerant at a sufficiently high ratio to provide adequate cooling.

[0005] Due to the relative position of the electric motor and the magnetic bearing, the refrigerant used to cool the electric motor can move towards the magnetic bearing, causing it to overcool. This can be especially common when the compressor is operating at low loads (as less heat is generated by the motor, leading to more refrigerant buildup). When overcooled, the magnetic bearing can contract. This can cause problems with sensors mounted to the magnetic bearing. These sensors are typically used to measure the relative distance between the bearing and adjacent components (such as rotating shafts). When overcooled, the sensors can malfunction (e.g., trigger bearing control) because the readings show a measured relative distance greater than acceptable.

[0006] Therefore, there remains a need for methods to manage cooling within the compressor in order to prevent or at least mitigate excessive cooling of the magnetic bearings. Summary of the Invention

[0007] According to one embodiment, a barrier is provided for controlling cooling within a sealed, cooled motor. The barrier includes an insulator surface, at least one fastener hole, and at least one vent hole. The insulator surface includes a first side and a second side. The insulator surface is configured to restrict the flow of working fluid. At least one fastener hole is disposed in the insulator surface. At least one vent hole is disposed in the insulator surface. At least one vent hole is configured to control the pressure difference between the first side and the second side.

[0008] According to additional or alternative embodiments, the barrier comprises an annular shape having an outer diameter and an inner diameter. At least one fastener hole may be arranged circumferentially adjacent to the outer diameter, and at least one vent hole may be arranged circumferentially adjacent to the inner diameter.

[0009] According to additional or alternative embodiments, the insulator surface is made of a material with low electrical and thermal conductivity.

[0010] According to additional or alternative embodiments, the material is Garolite.

[0011] According to another aspect of this disclosure, a compressor is provided, comprising an electric motor, a magnetic bearing, and a barrier arranged adjacent to the electric motor. The electric motor is used to drive a rotating shaft. The magnetic bearing is arranged adjacent to the electric motor. The barrier includes: an insulating surface configured to restrict the flow of working fluid, at least one fastener hole disposed in the insulating surface, and at least one vent hole disposed in the insulating surface. The at least one vent hole is configured to control a pressure difference between a first side and a second side.

[0012] According to additional or alternative embodiments, the barrier comprises an annular shape having an outer diameter and an inner diameter. At least one fastener hole may be arranged circumferentially adjacent to the outer diameter. At least one vent hole may be arranged circumferentially adjacent to the inner diameter.

[0013] According to additional or alternative embodiments, the shaft passes through the ring belt.

[0014] According to an additional or alternative embodiment, the compressor further includes a fastening assembly configured to secure the barrier to the magnetic bearing through at least one of the fastener holes.

[0015] According to additional or alternative embodiments, the fastening assembly includes at least one of a fastener, a washer, and a sleeve.

[0016] According to an additional or alternative embodiment, the compressor further includes at least one first jet disposed upstream of the barrier and at least one second jet disposed downstream of the barrier. The at least one first jet and the at least one second jet are configured to dispense working fluid.

[0017] According to additional or alternative embodiments, the dispensed working fluid is configured to pass through at least one vent.

[0018] According to additional or alternative embodiments, at least one first jet is configured to distribute working fluid to an electric motor.

[0019] According to additional or alternative embodiments, at least one second jet is configured to distribute working fluid to the magnetic bearing.

[0020] According to additional or alternative embodiments, the working fluid is in a substantially liquid phase.

[0021] According to additional or alternative embodiments, the working fluid is R-134A refrigerant.

[0022] According to additional or alternative embodiments, the compressor is a centrifugal compressor.

[0023] According to additional or alternative embodiments, the compressor is an axial compressor.

[0024] According to additional or alternative embodiments, the compressor is a scroll compressor. Attached Figure Description

[0025] The subject matter of this disclosure is specifically pointed out and clearly claimed in the claims at the end of the specification. The following description of the drawings should not be considered as limiting in any way. Referring to the drawings, similar element numbers are similar:

[0026] Figure 1 This is a cross-sectional side view of the compressor, which shows the flow of the working fluid used for cooling the magnetic bearing according to one aspect of this disclosure.

[0027] Figure 2 This is a cross-sectional side view of the compressor, which shows the flow of the working fluid used for cooling an electric motor according to one aspect of this disclosure.

[0028] Figure 3 A perspective view of a barrier according to one aspect of this disclosure.

[0029] Figure 4 For one aspect of this disclosure Figure 3 The barrier shown is in Figure 1 and Figure 2 The image shows a cross-sectional side view of the assembly inside the compressor.

[0030] Figure 5 For one aspect of this disclosure Figure 3 The barrier shown is in Figure 1 and Figure 2 The diagram shows a disassembled cross-sectional side view of the compressor. Detailed Implementation

[0031] As will be described below, a barrier for controlling cooling within a sealed, cooled motor and a compressor comprising the barrier are provided. The barrier makes it possible to prevent or at least mitigate overcooling of the magnetic bearing within the compressor. In some cases, the barrier acts as a protective boundary by limiting the flow of refrigerant from the compressor's electric motor toward the compressor's magnetic bearing. By utilizing the barrier to limit the refrigerant flow, cooling of the magnetic bearing within the compressor can be managed without active control (e.g., actively regulating the amount of refrigerant dispersed by one or more jets).

[0032] Although it is anticipated that barrier 110 can be used in any hermetically cooled motor, for the sake of brevity, barrier 110 is described as being used in compressor 100, for example, compressor 100 with electric motor 130 and magnetic bearing 120. Figure 1 and Figure 2 An exemplary depiction of a barrier 110 within a compressor 100 having an electric motor 130 and a magnetic bearing 120 is shown. The electric motor 130 is used by the compressor 100 to drive a rotating shaft 140. The magnetic bearing 120 is used by the compressor 100 to magnetically levitate the rotating shaft 140. To control cooling within the compressor 100 (e.g., to prevent overcooling of the magnetic bearing), the barrier 110 is configured between the electric motor 130 and the magnetic bearing 120.

[0033] Barrier 110 includes an insulator 111, at least one fastener hole 112, and a vent 113. Barrier 110 is configured such that one side (e.g., a first side 180) is adjacent to the electric motor 130, and another side (e.g., a second side 190) is adjacent to the magnetic bearing 120. Barrier 110 is configured to restrict the flow of working fluid (e.g., refrigerant) between the electric motor 130 and the magnetic bearing 120. By restricting the flow of working fluid, barrier 110 helps to prevent or at least mitigate overcooling of the magnetic bearing 120 within the compressor 100 in certain circumstances.

[0034] To facilitate the distribution of working fluid (e.g., refrigerant) through compressor 100, compressor 100 may include at least one jet 150. Jet 150 may be any orifice capable of injecting an effective amount of working fluid into compressor 100 to prevent overheating. In some cases, compressor 100 includes at least one jet 150 upstream of barrier 110 and at least one jet 150 downstream of barrier 110. The jet 150 upstream of barrier 110 may be used to distribute working fluid to cool electric motor 130. The jet 150 downstream of barrier 110 may be used to distribute working fluid to cool magnetic bearing 120. By being configured between electric motor 130 and magnetic bearing 120, barrier 110 restricts the flow of working fluid between electric motor 130 and magnetic bearing 120. By restricting the flow of working fluid through barrier 110, in some cases, it helps to prevent or at least mitigate overcooling of magnetic bearing 120.

[0035] In some cases, the working fluid injected into the first side 180 and the second side 190 of the barrier is in a substantially liquid phase. A substantially liquid phase can be interpreted as meaning that the working fluid is more in the liquid phase than in the gas phase. In some embodiments, the barrier 110 allows the working fluid to flow from the second side 190 of the barrier 110 to the first side of the barrier 180, such that the working fluid can be delivered to the discharge port 131 in the electric motor 130. In some cases, the working fluid is R-134A refrigerant. In some embodiments, the compressor is a centrifugal compressor, an axial compressor, or a scroll compressor.

[0036] Figure 3 The image shows a perspective view of a barrier 110 according to one aspect of the invention. The barrier 110 includes features for limiting a first side 180 and a second side 190 (in...). Figure 1 and Figure 2 The barrier 110 is an insulator for the flow of working fluid (e.g., refrigerant) between the insulator and the magnetic bearing 120 (shown in the diagram). The barrier 110 also includes at least one fastener hole 112 arranged in the insulator 111 such that the insulator 111 can be secured to the magnetic bearing 120 and / or the bearing housing 121. To secure the insulator 111, at least one fastener (e.g., one or more shoulder bolts) is used. Figure 4 and Figure 5 As shown in the diagram, the barrier 110 can be inserted through at least one fastener hole 112. The barrier 110 also includes at least one vent hole 113 for controlling the pressure difference between the first side 180 and the second side 190.

[0037] In some cases, the vent 113 is configured to pass through the insulator 111 using at least one hole. At least one hole can be used to allow rotation of the shaft 140 (in... Figure 1 and Figure 2(As shown in the diagram). When a hole for the rotating shaft 140 is included, the hole for the rotating shaft 140 may be a vent 113 (e.g., allowing control of the pressure difference between the first side and the second side). For example, the hole used to allow the rotating shaft 140 to pass through may be wide enough in diameter to create a gap between the insulator 111 and the rotating shaft 140. In some cases, this gap helps to control the pressure difference between the first side 180 and the second side 190.

[0038] Conversely, the vents 113 can be provided using any number of holes spaced in any manner and configured in any shape (e.g., circular, square, etc.), allowing for effective control of both the flow of the working fluid and the pressure differential between each side 180, 190 of the barrier 110. Effective control of the working fluid flow can be considered as allowing the working fluid to be delivered to the magnetic bearing 120 in a manner that prevents overheating and overcooling. Effective control of the pressure differential can be considered as preventing a substantial difference in pressure between each side 180, 190 of the barrier 110. A substantial pressure difference is a point that can adversely affect the structure of the barrier.

[0039] In some cases, insulator 111 is made of a material with low electrical and thermal conductivity. For example, insulator 111 may be (at least partially) made of G10-FR4 (commonly referred to as "Garolite"). However, it is contemplated that insulator 111 may be made of any material capable of restricting the flow of the working fluid. For example, insulator 111 may be (at least partially) made of a variety of different plastic materials and / or polymers with low electrical and thermal conductivity.

[0040] To allow the barrier 110 to expand and contract due to the thermal effect of the working fluid, in some cases, each corresponding fastener 112 may use a spring washer 114. Figure 4 and Figure 5 The use of a fastener 112 with a spring washer 114 is illustrated. The spring washer 114 can be any type of spring washer 114, such as a butterfly spring washer, a corrugated spring washer, a finger spring washer, or a wave spring washer. Regardless of the type of spring washer 114 used, in some cases, the spring washer 114 is used to allow the barrier 110 to expand and contract without generating or at least minimizing stress in the vicinity of the fastener 112.

[0041] like Figure 4 and Figure 5As shown, in some cases, the barrier 110 is secured by inserting the fastener 112 into the magnetic bearing 120 and / or the bearing housing 121. In some cases, a sleeve 115 may be used to transfer clamping force from the fastener 112 (e.g., from the head of the shoulder bolt) to the housing 121. In some cases, the sleeve 115 is a tube of sufficient length and diameter to allow the passage of the fastener 112. In some cases, the sleeve 115 helps reduce the stress on the insulator 111 caused by the fastener 112 (e.g., where the clamping force of the fastener 112 is applied directly to the insulator 111, the stress on the insulator 111 can be relatively higher than the stress on the insulator 111 when the sleeve 115 is used).

[0042] As in Figure 3 As shown, in some cases, the barrier 110 is configured in an annular shape having an outer diameter 117 and an inner diameter 116. In some cases, at least one fastener hole 112 is circumferentially arranged near the outer diameter 117. In some cases, at least one vent hole 113 is circumferentially arranged near the outer diameter 116. As described above, the design and configuration of the components of the barrier 110, and its positioning within a sealed, cooled motor (e.g., a compressor), allow for relatively simple techniques to prevent or at least mitigate overcooling of the magnetic bearing 120.

[0043] While this disclosure has been described with reference to one or more exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereunder without departing from the scope of this disclosure. Furthermore, many modifications may be made to suit particular situations or materials to the teachings of this disclosure without departing from its essential scope. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed as the best mode contemplated for carrying out this disclosure, but rather that this disclosure will include all embodiments falling within the scope of the claims.

Claims

1. A compressor, comprising: An electric motor used to drive a rotating shaft; as well as A barrier for controlling cooling within a sealed cooling motor, the barrier comprising: An insulator surface including a first side portion and a second side portion, the insulator surface being configured to restrict the flow of working fluid; At least one fastener hole disposed in the surface of the insulator; and At least one vent is disposed in the surface of the insulator, the at least one vent being configured to control the pressure difference between the first side and the second side; in, The compressor includes a magnetic bearing arranged adjacent to the electric motor, and The barrier is arranged between the electric motor and the magnetic bearing.

2. The compressor according to claim 1, characterized in that, The surface of the insulator is composed of a material with low electrical and thermal conductivity.

3. The compressor according to claim 2, characterized in that, The material is Garolite.

4. The compressor according to any one of claims 1-3, characterized in that, The barrier includes a ring shape having an outer diameter and an inner diameter; and wherein the at least one fastener hole is arranged circumferentially adjacent to the outer diameter, and the at least one vent hole is arranged circumferentially adjacent to the inner diameter.

5. The compressor according to claim 4, characterized in that, The shaft passes through the ring belt.

6. The compressor according to claim 4, characterized in that, The compressor further includes a fastening assembly configured to secure the barrier to the magnetic bearing through at least one of the fastener holes.

7. The compressor according to claim 6, characterized in that, The fastening assembly includes at least one of a fastener, a washer, and a sleeve.

8. The compressor according to claim 1, characterized in that, The compressor further includes at least one first jet disposed upstream of the barrier and at least one second jet disposed downstream of the barrier; the at least one first jet and the at least one second jet are configured to dispense the working fluid.

9. The compressor according to claim 8, characterized in that, The allocated working fluid is configured to pass through the at least one vent.

10. The compressor according to claim 8, characterized in that, The at least one first jet is configured to distribute the working fluid to the electric motor.

11. The compressor according to claim 8, characterized in that, The at least one second jet is configured to distribute the working fluid to the magnetic bearing.

12. The compressor according to claim 8, characterized in that, The working fluid is in a substantially liquid phase.

13. The compressor according to claim 8, characterized in that, The working fluid is R-134A refrigerant.

14. The compressor according to claim 1, characterized in that, The compressor is a centrifugal compressor.

15. The compressor according to claim 1, characterized in that, The compressor is an axial compressor.

16. The compressor according to claim 1, characterized in that, The compressor is a scroll compressor.

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